This invention relates to a method and apparatus for forming a shoe shank on the bottom of a shoe insole to stiffen the shank region which extends from the heel breast to the ball region. More particularly, the present invention is directed to a method and apparatus for applying, locating, retaining and curing a flexible strip of activatable thermosetting resinous material, directly in situ on the shoe bottom so that the strip may conform to the contour of the shoe bottom and adhere thereto in its stiffened, hardened form. Such strips are described in pending U.S. Patent Application Ser. No. 681,582, filed Apr. 29, 1976, now U.S. Pat. No. 4,081,917, issued Apr. 4, 1978; and in U.S. Patent Application Ser. No. 765,096, filed Feb. 3, 1977, both of said applications being assigned to the assignee of this application.
The present invention relates to further improvements to the method and apparatus described in my prior U.S. Patent Application Ser. No. 765,095, filed Feb. 3, 1977, now U.S. Pat. No. 4,122,573, issued Oct. 31, 1978.
Use of flexible, in situ-activatable strips to form a shank stiffener solves numerous problems which have been presented in the prior art of shoe manufacture. As described in Application Ser. No. 681,582, shank stiffeners typically have been inserted in shoes in the form of a stiff wood or steel pre-formed member. Because of a wide variety of styles and sizes of shoes, the typical prior art practice has required the manufacturer to maintain an inventory of a wide variety of different sizes and shapes of shanks. Numerous difficulties have been presented in the storage, proper selection and insertion of such shanks. The present invention relates to a method and apparatus by which an initially flexible and deformable shank strip may be formed directly in place on the shoe bottom to conform precisely to the shape of the insole bottom and be hardened in situ thereon by an external stimulus such as radiant energy.